import com.sun.xml.internal.ws.api.model.wsdl.WSDLOutput;
import jdk.internal.org.objectweb.asm.tree.MultiANewArrayInsnNode;

import java.util.*;
class Person
{
    int age;

    public Person(int age) {
        this.age = age;
    }
}

public class text170 {
    public static void main(String[] args) {
        HashSet<Person>b=new HashSet<>();
        b.add(new Person(5));
        b.add(new Person(6));
        System.out.println(b);


    }
    public static void main2(String[] args) {

        //b.add(null);
        //System.out.println(b);

    }


    public static void main1(String[] args) {
     //HashMap<Integer,String>a=new HashMap<>();





    }
}
